The present invention relates to product checkout devices and more specifically to ambient light sensing apparatus and method for a produce data collector.
Bar code readers are well known for their usefulness in retail checkout and inventory control. Bar code readers are capable of identifying and recording most items during a typical transaction since most items are labeled with bar codes.
Items which are typically not identified and recorded by a bar code reader are produce items, since produce items are typically not labeled with bar codes. Bar code readers may include a scale for weighing produce items to assist in determining the price of such items. But identification of produce items is still a task for the checkout operator, who must identify a produce item and then manually enter an item identification code. Operator identification methods are slow and inefficient because they typically involve a visual comparison of a produce item with pictures of produce items, or a lookup of text in table. Operator identification methods are also prone to error, on the order of fifteen percent.
A produce data collector disclosed in the co-pending application includes a spectrometer. The spectrometer preferably includes a linear variable filter (LVF) and a linear diode array (LDA), which capture spectral information about a produce item. In operation, an operator places a produce item on a window of the produce data collector, a light source illuminates the produce item through the window, and the produce data collector captures the spectrum of the diffuse reflected light from the produce item.
To improve system efficiency and prolong the life of the light source, it is highly desirable to operate the produce data collector in a xe2x80x9cflashingxe2x80x9d mode, such that the light source is only turned on while an object is in place on the window and while spectral data is being captured. Triggering may be manual or automatic, with automatic triggering being the preferred choice. As disclosed in the co-pending application, manual triggering envisions operator intervention to operate a switch or initiate execution of a software command. Automatic triggering may be initiated in response to a drop in ambient light entering the produce data collector.
However, ambient light sensing methods may not always be able to distinguish between an item which is on the window and an item which is above the window. Thus, false triggering may occur during movement of the item towards the window.
Therefore, it would be desirable to provide ambient light sensing apparatus and method for a produce data collector which provides more accurate triggering of data capture.
In accordance with the teachings of the present invention, ambient light sensing apparatus and method for a produce data collector are provided.
The apparatus includes an image capture device which has a first receiving angle for incident light through an aperture in the produce data collector which is larger than a second receiving angle of a collector within the produce data collector which collects produce data.
A method of activating a produce data collector includes the steps of determining an average dark level with an aperture in the produce data collector covered, receiving light signals from an image capture device in the produce data collector, determining an average light level, comparing the average dark level to the average light level, and if the average light level is within a predetermined distance of the average dark level, activating the produce data collector.
It is accordingly an object of the present invention to provide ambient light sensing apparatus and method for a produce data collector.
It is another object of the present invention to provide ambient light sensing apparatus and method for a produce data collector which provide more accurate triggering of data capture.
It is an other object of the present invention to provide ambient light sensing apparatus and method for a produce data collector which employs pinhole cameras to more accurately sense a drop in ambient light.